A device management method has been suggested (see Japanese Patent Publication No. 4321774) that uses an electrical outlet that detects the activation of connected device and notifies a device management server of the installation place of the electrical outlet and the device management server that receives the activation notification from the device. When the notification is received from both the electrical outlet and the device within a predetermined time interval, the device connected to the electrical outlet is determined to be identical to the device relating to the activation notification.
Further, a variety of techniques have been suggested for transmitting the information relating to electrical outlets via a network (see Japanese Patent Publication No. 3843894 and Japanese Patent Application Publication Nos. 2004-23497 and 2010-114967).